3
Historical Perspective  Electrical cardiac pacing for the management of brady-arrhythmias was first described in 1952  Permanent transvenous pacing devices were first introduced in the early 1960’s

11
Electrocardiogram During Cardiac Pacing  Pacemaker has two main functions:  Sense intrinsic cardiac electrical activity  Electrically stimulate the heart  VVI- senses intrinsic cardiac activity in the ventricle and when a preset interval of time with no ventricular activity occurs it depolarizes the right ventricle causing ventricular contraction

13
Electrocardiogram  Dual chamber pacer is more complicated because the pacer has the ability to both sense and pace either the atrium or the ventricle  Possible to have only atrial, only ventricular or both atrial and ventricular pacing  DDD pacer is a common example of this

16
Magnet Placement  The EKG technician should perform a 12 lead cardiogram and then a rhythm strip with a magnet over the pacer  Often a very poorly understood concept by the non-cardiologist  Does not inactivate the pacer as is commonly believed  Activate a lead switch present in the pacemaker which converts the pacer to a asynchronous or fixed-rate pacing mode  Inhibits the sensing function of a pacemaker

27
Case 2  72 year old male presents to the emergency room after a fall, tripped over a bath mat, no LOC  Shortened and rotated left leg  Past history – pacemaker, hypertension  Nurse does an routine pre-op CXR and EKG

30
Septal Perforation  Usually identified at the time of pacer insertion but leads can displace after insertion  Can occur with transvenous pacer insertion  Keys diagnosis are a RBBB pattern on EKG and a pacer lead displaced to the apex of the heart on CXR

31
Septal Perforation  Management:  Notify the pacer service  Pacer wire has to be removed but not emergently  Small VSD which heals spontaneously

32
Conclusions  Pacemakers are becoming more common everyday  We need to understand basic pacing terminology and modes to treat patients effectively.  Most pacer malfunctions are due to failure to sense, failure to capture, over-sensing, or in- appropriate rate  Standard ACLS protocols apply to all unstable patients with pacemakers.